1. Field of the Invention
The present invention relates to an audio/video stream transmission method and, more particularly, to a method for preventing disconnection of audio/video streams that is capable of continuously providing audio/video streams without disconnection to a screen when the audio/video streams are transferred to a plurality of renderers through a home network.
2. Description of the Background Art
In general, a home network is an environment in which home network devices at a home are connected as one network to share mutual information and use a broadband communication.
That is, the home network refers to a technique or a service that home network devices, such as a computer related equipment or an A/V device, a control or security device for home automation, an entertainment device such as a game machine, are all connected as one communication network (or home network) to share and control mutual information.
In the home network, one of the home network devices is set as a server while the other home network devices are set as renderers, thereby sharing and controlling mutual information.
FIG. 1 illustrates connection between the server and plural renderers by home network.
As shown in FIG. 1, the server 10 and first and second renderers are connected to the home network 20. The server 10 can be a medium reproducing unit for reproducing data, while the first and second renderers 11 and 12 can be a notebook computer or a DTV (Digital Television) for outputting audio/video streams received from the server 10 on a screen.
Accordingly, as the server 10 reads the A/V streams recorded in an optical recording medium reproducing unit and transmits it to the first and second renderers 11 and 12, a user can enjoy an audio/video content outputted from the first and second renderers 11 and 12.
The medium reproducing unit operating as a server includes a header for reading the A/V streams recorded in a storing medium such as a DVD (Digital Versatile Disc) or a hard disk.
FIG. 2 illustrates a hard disk medium reproducing unit as a server for reproducing the A/V streams.
As shown in FIG. 2, the hard disk medium reproducing unit 30 includes: a platter 31, a metal disk plate with a magnetic substance, for storing data, a spindle motor 32 for rotating the platter 31, a header 33 for reading and writing data to and from the platter 31, a header arm 34 for moving the header to a desired address on the platter 31, and a controller 35 including a circuit board for driving each part and controlling operations.
When a data reproducing command is received from a user, the hard disk medium reproducing unit 30 mechanically moves the header 33, reads a corresponding A/V stream existing at a certain position of the platter and outputs it externally. Then, the renderer reproduces the A/V stream outputted from the hard disk medium reproducing unit 30 and the user can enjoy the content of the A/V stream.
Different content A/V streams as recorded in the storing medium of the hard disk medium reproducing unit 30 are recorded in different positions on the platter 31.
That is, as shown in FIG. 1, if two or more renderers request different A/V streams from the server, the header of the server reads two or more A/V streams while mechanically moving to the A/V stream-recorded positions in turn with certain time difference, and outputs them, causing a problem that transmission of A/V streams is slow.
In other words, in the case that one header makes a mechanical position movement to read two or more A/V streams, it takes long time to reproduce the audio/video streams beyond a range that a certain amount of audio/video streams are read and outputted within predetermined time.
Thereafter, as the A/V streams outputted from the server is delayed in its transmission, the renderer fails to output the certain amount of audio/video streams within predetermined time defined as a standard. Then, the A/V streams are disconnected midway, distorted or unrecognizable in form, changing from the content of the original A/V streams, resulting in a problem that an abnormal image is outputted.
In order to solve the problem, the conventional adds a memory in the renderer in order to receive the A/V streams for about 3 seconds to 5 seconds, to thereby output a normal image.
Namely, when a situation occurs that A/V streams are temporarily restrained from being reproduced due to a transmission delay, the already received A/V streams are supplied to a decoder without disconnection through the memory for a few seconds, so that a normal content with the original audio/video streams can be outputted on the screen.
However, the solution for the problem by adding the memory to the renderer causes an additional fabrication cost. In addition, if A/V stream transmission is continuously delayed because of simultaneous connection by plural renderers, the audio/video streams would not remain, resulting in a problem that a disconnection phenomenon or a distortion phenomenon occurs on the screen.